Counterfeit electronic components have become a serious concern in recent years. Counterfeit electronic components can jeopardize the performance and reliability of the products in which they are used. Counterfeit component detection, as well as other applications, such as data security and encryption, may employ the use of chip identification in the form of a physical unclonable function (PUF). A PUF is a function that is embodied in a physical structure and is easy to evaluate but hard to predict. Ideally, an individual PUF device must be easy to make but practically impossible to duplicate, even given the exact manufacturing process that produced it. As there is an ever-increasing need for data security and authentication, it is desirable to have improved methods and circuits for implementing chip identification.